Negative pressure wound treatment devices (vacuum wound treatment devices) have been described many times, in particular, in US 2004/0073151 A1, WO 2009/047524 A2, EP 1 905 465 A1, WO 2008/039314 A2 or EP 777 504 B1 as well as in EP 1 863 549 B1, EP 2 464 394 A1, WO 2012/156174 A1 or EP 2 464 393 A1 of the assignee.
In devices of this type for negative pressure wound therapy (npwt), a suction pump (sometimes incorrectly called “vacuum pump”) communicates with the wound or the wound area via a suction line, wherein a wound dressing and an air-tight cover material is provided for air-tight sealing of the wound and the wound area, such that a negative pressure can be generated in the wound region and fluids can be extracted by suction from the wound region.
The term negative pressure in connection with the present invention defines an air pressure that is lower than the ambient air pressure (atmospheric air pressure). The cover material of a wound dressing for air-tight sealing of a wound region must therefore be designed in such a fashion that it withstands the pressure difference that is established such that a negative pressure can actually be applied to and maintained in the wound region. The wound dressing and the cover material are, however, typically flexible to a certain degree. In the field of negative pressure therapy for the treatment of wounds, the negative pressure is quantitatively defined as the pressure difference between ambient air pressure and the air pressure applied below the cover material. In the field of negative pressure therapy, this pressure difference is typically at most 250 mmHg (mm mercury column) (1 mm Hg=1 Torr=133.322 Pa). This negative pressure range of up to maximally 250 mmHg has turned out to be suitable for wound healing. A preferred negative pressure range is between 10 and 150 mmHg.
For typical negative pressure treatment, the negative pressure that is applied to the wound using the device can either be kept substantially constant with time or can be varied with time, in particular in cycles which can be realized by a correspondingly designed and programmed control device for the negative pressure-generating device, in particular in dependence on further parameters.
An advantageous flexible suction line, e.g. in the form of a drainage hose, is provided for applying a negative pressure and advantageously also for extracting body fluids, the drainage hose communicating at one end with the wound area or the wound region via a so-called port in the area of the wound cover material, and at the other end communicating with a container for receiving the sucked body fluids or with the negative pressure generating device.
In addition to negative pressure wound treatment, the present invention may also be used for other applications for providing a negative pressure for medical applications, in particular, extraction of any body fluids by suction, in the field of medical incontinence management, in the field of care of stoma patients or in the field of extraction of wound exudates, if necessary, thereby using rinsing liquids and also without application of a negative pressure over considerable time periods.
In general, negative pressure wound therapy apparatuses are available as stationary or as portable devices. The before-mentioned definition “portable device” means that the patient can carry the device along so that he/she is mobile and his/her wound can nevertheless be permanently treated, i.e. without interruption. The portable device may thereby be held on the body of the patient and be carried along by means of any fastening means, for example in the form of a flexible belt or a shoulder strap. A portable device of the above-mentioned type naturally may also be used for stationary operation, i.e. detached from the body of the patient. In this case, it may e.g. be mounted to a hospital bed or be deposited next to the hospital bed.